[autoloanexpert]

Four ladies! I thought one would be more than enough as it is!

Forget chocolate as a gift, thats a western thing. Anyway she certainly wouldnt want such a gift that's gonna help her put on an extra few pounds!

Some over types of light candy would be appreciated as long as its foreign.

Colour want mean the slightest!

A nice gift that a Thai would appreciate is something from your hometown. Just like paul_au said there about a souvenir t-shirt.
A picture, a doll, something to stick on the TV, anything like that, that you cant find over here.